Self-bear furniture modules and elements made of metal, in particular made of a die-cast aluminum alloy, and process for their possible surface finishing

ABSTRACT

A self-bearing furniture module or element ( 1 ) is described, made of a die-cast aluminium alloy, and comprising: an elongated supporting structure ( 3 ) with two ends ( 5, 7 ) and equipped with at least one first engaging element ( 9, 11 ); at least one bearing component ( 12, 14 ) connected to the supporting structure ( 3 ) adjacent to the first engaging element ( 9, 11 ); and at least one engaging component ( 16, 18 ) connected to the supporting structure ( 3 ) in a central part thereof at the same distance from the two ends ( 5, 7 ); the engaging component ( 16, 18 ) is equipped with at least one second engaging element ( 20, 22 ) and is adapted to engage a respective bearing component ( 12, 14 ) of another furniture module or element through operative coupling of the corresponding first and second engaging elements ( 9, 11  and  20, 22 ). A process is also described, for the possible surface finishing of such furniture module or element ( 1 ).

The present invention refers to self-bearing furniture modules and elements made of metal, in particular made of-a die-cast-aluminium alloy, both rough and finished with the application of various surface preparation techniques or made noble, with a treatment variation, decorative and protecting deposit.

As regards such furniture modules and elements, the following prior art document are known in the art:

1) Italian Patent PD2004A000161, filed on 23 Jun. 2004, entitled “Tessera per mosaico and metodo di fabbricazione della medesima”; and

2) Italian Patent PD2007A000134, filed on 12 Apr. 2007, entitled “Piastrella per la composizione mosaici”.

These patents cover the manufacture of tiles with plane shapes made of an aluminium alloy through plastic deformation, obtained by cutting a slab and afterwards enamelled on their surface with glass-type enamels.

3) International Patent N° WO2006/013115A1, filed on 9 Feb. 2006, entitled “Method for the protection/selective colouring of an endproduct”.

This patent deals with the formulation of coloured coatings based on titanium (or similar elements, Nb, Zr, etc.) and its related oxides. Such coatings can be obtained through deposition of a titanium film with PVD technique, and following anodisation to obtain increasing oxide thickness, or through direct PVD deposition of titanium oxide with increasing thickness and the following generation-of interference colours.

4) U.S. Pat. No. 3,833,484 and corresponding Italian Patent IT 948709, filed on 3 Sep. 1974, entitled “Method of forming an integral colored anodic oxide on aluminum pressure die casting”.

This method consists in creating a uniform anodic layer by subjecting the object surface, obtained through pressure die casting of an alloy of aluminium with 0.1-1.3% of chrome and 0.2-3.4% of manganese, to an anodisation treatment.

5) International Patent W0010951, filed on 8 Feb. 2001, entitled “Decorative coating”.

This patent deals with the creation of a decorative coating with magnetron sputtering technique. Due to this technique, a protecting transparent coating is deposited, whose thickness determines the final colour of the deposited surface.

6) International Patent W02006013115, filed on 9 Feb. 2006, entitled “Method for the protection/selective colouring of an endproduct”;

7) Korean Patent KR20020091535, filed on 6 Dec. 2002, entitled “Multilayered interference film”;

8) Japanese Patent JP10230563, filed on 2 Sep. 1998, entitled “Interference color article and its manufacture”;

9) U.S. Pat. No. 5,409,782, filed on 25 Apr. 1995, entitled “Composite film”;

10) Japanese Patent JP2002274101, entitled “Surface Treatment method of album alloy wheel”.

These patents disclose method for obtaining interference colouring effects by applying multi-layer coatings.

11) U.S. Pat. No. 3,086,629 and U.S. Pat. No. 2,710,175, which disclose a self-bearing furniture module or element according to the preamble of claim 1.

Therefore, object of the present invention is solving the above prior art problems by providing a furniture element, composed of metal modules, preferably made of an aluminium alloy, in particular obtained through die-casting, and finished with the application of various techniques for preparing the surface, and as variation subjected to a treatment with a double-layer deposit, whose function is both decorative, and protective.

The single modules can have variable shapes (ex. curvilinear or square), but all have the peculiarity of containing a zone shaped in such a way as to be able to create, without the need of fastening with small blocks, an efficient engagement with nearby modules, making the deriving structure (global furniture element) self-bearing.

The connection between one piece and another is generated through a simple mechanical engagement, due to the strict geometric tolerances, and consequently the minimum play guaranteed between the pieces.

The global self-bearing structure thereby generated is adapted to be used, for example, as wall coating with bas-relief, as dividing wall, equipped with filled parts and empty parts, or as decorative element per se.

The characteristic of these elements is further linked to the fact that they are capable of being easily installed and already surface treated, and do not need therefore further finishing operations. In fact, differently from wall coatings traditionally used in the building sector, the modules described here have more complex shapes than the simple rectangular or square tiles: they can have curved shapes, with alternate filled and empty areas, and also have relieved or recessed regions, in order to create bas-relief structures (thereby pointing out drawings, motifs or company logos).

Such modules, once mutually engaged, generate a furniture element with design and lightness properties conferred both by the empty spaces present in the structure, and by the composing material, aluminium. The product creates a new behavioural assumption in the end user, since it does not need specialisations or specialists for its laying, does not need other binding materials or a supporting structure. The technique for producing the single modules, die casting, allows manufacturing quickly and in big amounts, components with complex shapes and small and medium sizes.

This further results in an economic and highly flexible process, from the point of view of possible modifications that can be made to module shapes and sizes. The die-casting technique has been used above all for producing components, namely subparts of more complex systems, especially in the mechanical sector. In this case, die-casting is used for producing a complete finished product, and not a single component, aimed for the building/architecture sector. On the other hand, due to the die-casting technology, it is possible to guarantee high flexibility on geometries that can be made (ex. the introduction of simple inserts in the die allows modifying its configuration) and high productivities, with consequent reduction of costs.

The above and other objects and advantages of the invention, as will appear from the following description, are obtained with a furniture module or element as claimed in claim 1, and with the related process described in the corresponding claim.

Preferred embodiments and non-trivial variations the present invention are the subject matter of the dependent claims.

It will be immediately obvious that numerous variations and modifications (for example related to shape, sizes, arrangements and parts with equivalent functionality) can be made to what is described, without departing from the scope of the invention as appears from the enclosed claims.

The present invention will be better described by some preferred embodiments thereof, provided as a non-limiting example, with reference to the enclosed drawings, in which:

FIG. 1 shows a top view of an embodiment of a furniture element according to the present invention;

FIG. 2 shows a side sectional view of the furniture element of FIG. 1 performed along section line A-A;

FIG. 2A shows a perspective view of the furniture element of FIG. 1:

FIG. 3 shows a top view of two mutually coupled furniture elements of FIG. 1;

FIG. 4 shows a side sectional view of the furniture elements of FIG. 2 performed along section line C-C; and

FIG. 5 shows a top view of further embodiment of a furniture element according to the present invention.

With reference to the Figures, they simply show an embodiment of a furniture element 1 according to the present invention: it will be immediately obvious for the experts in the field that the external and aesthetic shape of the inventive furniture element 1 can be various, and will not be limited to the one shown. The construction peculiarities with which the furniture element 1 is equipped are its innovative characteristic, allowing its coupling with other furniture elements 1, even with mutually different shapes, as shown for example in FIG. 3.

The furniture module or element 1 of the present invention is self-bearing, is made of a die-cast aluminium alloy, and substantially comprises:

an elongated supporting structure 3 comprising two ends 5, 7 and equipped with at least one first engaging element 9, 11 placed at one of the ends 5, 7;

at least one bearing component 12, 14 connected to the supporting structure 3 adjacent to the first engaging element 9, 11; and

at least one engaging component 16, 18 connected to the supporting structure 3, said engaging component 16, 18 being equipped with at least one second engaging element 20, 22 and being adapted to engage a respective bearing component 12, 14 of another furniture module or element through operative coupling of the corresponding first and second engaging elements 9, 11 and 20, 22.

The innovative part of the invention is that the bearing components 12, 14 are two, each one shaped as a regular geometric figure (for example a circle, a square, a rectangle, a rhombus, etc.), with a maximum overall size (for example, a diameter for a circle, a base for a square, a longer side for a rectangle or a rhombus, etc.) of a same order of magnitude of the length of the supporting structure 3, and the engaging components 16, 18 are also two, each one shaped as the same regular geometric figure of the bearing components 12, 14 with a maximum overall size of a same order of magnitude of the length of the supporting structure 3, the overall size of the engaging components 16, 18 being greater than the overall size of the bearing components 12, 14, in order to be able to place an engaging component 16, 18 of a first furniture module or element 1 around and in engaging contact with the corresponding bearing component 12, 14 of a second furniture module or element 1, when the first and the second modules 1 are-mutually joined.

In the inventive embodiment shown in the Figures, the bearing components 12, 14 are two, of a circular shape, and the engaging components 16, 18 are also two, of a circulat shape and with greater diameter than the diameter of the bearing components 12, 14, in order to be able to place an engaging component 16, 18 of a first furniture module or element 1 around the corresponding bearing component 12, 14 of a second furniture module or element 1, when the first and the second modules 1 are mutually joined.

Moreover, in the configuration shown in FIGS. 1 to 4, the bearing components 12, 14 are placed at the two ends 5, 7 of the supporting structure 3 along its longitudinal axis, while the engaging components 16, 18 are centrally placed with respect to the supporting structure 3 and along an axis that is perpendicular to the longitudinal axis of the structure 3 itself: “cloverleaf” arrangement of the furniture module or element 1 is thereby obtained, as shown in FIG. 1; when the same module 1 is coupled with a module 1 of a corresponding shape, instead, the configuration of FIG. 3 is realised.

Coupling between modules 1 is obtained, in the case shown in FIGS. 1 to 4, by inserting, through an offset inclination, a bearing component. 12, 14 inside the shape (circle, for example) of an engaging component 16, 18, and coupling the two components so that their respective “arrow-shaped” projections 32, 36 of their respective bearing components 12, 14 are placed in the corresponding housing seat 30, 34 of the engaging components 16, 18.

In some of the projections 32, 36, holes 38, 40 are possibly provided (as shown in FIG. 3), that are used for inserting therein fastening elements (nails, screws, small blocks, etc.), for example on a wall, of a set of several furniture modules or elements 1, in order to use the bearing wall as support for the final composite furniture element.

It is obvious that, as already seen, the configurations of the furniture module or element 1 can be various, according to shape and arrangement of the different components. For example, FIG. 5 shows a second preferred, and also non-limiting, embodiment, in which the furniture modules or elements 1 are wholly made with a circular shape (including the supporting structure 3), with the coupling between dark module 1 and white module 1 performed as shown.

In FIG. 5, the furniture module or element 1 shown provides that the bearing components 12, 14 are two, of a circular shape, and are arranged with their diameter axes mutually perpendicular, and the engaging components 16, are also two, of a circular shape, with a greater diameter than the diameter of the bearing components 12, 14, with their diameter axes mutually perpendicular and respectively coinciding with the diameter axes of the bearing components 12, 14, in order to be able to place an engaging component 16, 18 of a first furniture module or element 1 around the corresponding bearing component 12, 14 of a second furniture module or element 1, when the first and the second modules 1 are mutually joined.

The furniture element 1 in its final use shape can be both rough, and surface-finished.

Finishing of the surface can be obtained through a decorative coating, that is obtained by depositing, on the metallic alloy, suitably prepared through deposition techniques from vapour phase, two coating layers that will be described in detail below.

The die-cast aluminium alloy, used as substrate, can be prepared with various techniques, such as sanding, hand-made or machine-made polishing, brushing, tumbling or buffing.

After having performed the above-described pre-treatment, the parts must be subjected to a washing procedure comprising:

1. blowing with compressed air (operation suitable to remove the presence contaminants as powder deposited on the surface);

2. keeping in a closed chamber, under vacuum conditions (of at least 10⁻² mbar) and at a temperature included between 20 and 200° C. (the set vacuum level and temperature produce degassing and the consequent removal of volatile species entrapped into the surface pores; the greater the vacuum level and the higher the temperature, the better the degassing efficiency; regarding the temperature, it is necessary to pay attention not to excessively rise in order not to incur in the risk of producing part distortions);

3. degreasing through solvents, such as acetone or ethyl alcohol (operation suitable to remove oily or greasy contaminants that can still be deposited on the surface of metals following working and handling).

After this washing stage, the parts must be handled with fabric gloves and transferred into the deposition chamber, in which the production of the coating occurs.

On such surface the deposition of at least a double layer deposit is carried out. In the examined case, deposition occurs, in a non-limiting way, by depositing on the furniture module or element 1 at least one first layer and at least one second layer. Both layers are composed of a mixture of two constituents with correspondingly and proportionally varying relative molar fractions: 1) a metallic material, for example iron, or another metal such as Ni or Ti (herein below for briefness, also called “Metal”), and 2) a silicon oxide- or silica-based material, or an oxide of another element of the Group IVA of the Periodic Table of Elements (herein below for briefness also called “Oxide”).

Fe, or Ti can be introduced in the layer both in a metallic and in a ionic form. Such constituents are co -deposited, in the same process tage, using various techniques described below.

The relative fractions of the two components can change, in order to change the refraction index, with values that, in the first layer, range from 0 to 1 for the metal and correspondingly and proportionally from 1 to 0 for the oxide, while in the second layer, range from to 0.9 for the metal and correspondingly and proportionally from 1 a 0.1 for the oxide.

In particular, the internal layer (in direct contact with the substrate) has prevailing metal, while the most external layer has prevailing oxide. The coating deriving from this double layer is, therefore, composed of a substantially reflecting internal layer, since it is very rich of metallic elements, and of a transparent layer, very rich in the oxide phase. The reflecting layer produces the reflection of incident light, the transparent layer, when the thickness change, generates different colours of an interference nature. The metal is added to the oxide in the two layers with a double function: modulating the oxide refraction index (in particular, the refraction index grows upon increasing the contents of the metallic element) and introducing a colouring component by absorption, characteristic of such element. For such reason, the produced coating has a colouring due to the combination of both interference and absorption effects. Under limit conditions, of a completely oxidic layer (relative molar fraction of the metal=0) or of a completely metallic layer (relative molar fraction of the oxide=0), in fact, completely transparent or completely reflecting single layers are respectively obtained. In all intermediate modulations of the relative molar fractions of oxide and metal, strong modulations of the refraction index are obtained and, therefore, the modification of the chromatic effect in terms both of tonality and of brightness.

The thickness of the first internal layer can range from a few hundreds of nanometers till a micrometer and, once having fixed its chemical composition, the thickness of the same layer does not introduce variations on the colouring.

The thickness of the external layer, with lower refraction index, instead determines the colour due to the interference component introduced with the transparent layer.

As already previously underlined, the colours produced by the deposit architecture described here have both an interference and an absorption nature. Due to the interference nature, when the thickness of the external transparent layer changes, colours are generated that repeat themselves in successive series due to a construction effect and change their tonality when the light wavelength, the light incidence angle and the angle with which they are observed, all change.

Due to the absorption nature, introduced by the addition of metal in the oxide layer, it is instead further possible to modulate the colour brightness. For such, reason, for low molar fractions of metals embedded in the external layer, light colouring are obtained, of the pastel type, while for high molar fractions of metals embedded into the external layer, darker and darker colourings are obtained.

The total thickness of the coating architecture (double layer) must anyway be limited to 1 micrometer. In fact, for greater thickness values, an excessive brightness lowering is obtained, consequently obtaining too dark colours.

The first layer, with prevailing metallic fraction, can be obtained by deposition with. Physical Vapour Deposition, PVD techniques (such as, for example, Sputtering, E-Beam, Cathode Arc, Thermal Evaporation, Ion Beam, etc.). The second layer, with prevailing oxide fraction, can be obtained through PVD deposition technique's, or through Plasma Enhanced Chemical Vapour Deposition (PECVD) techniques or other CVD technique. In addition to already described chromatic effects, the deposition of a layer mainly based on silicon oxide for PECVD can also allow obtaining, in the same process stage, a surface functionalisation, for example making hydrophilic, hydrophobic or anti-finger the thereby generated surface of the coating. Such benefits of the PECVD technique are known and already applied at industrial level, however, with all mentioned deposition techniques, and above all with PECVD, it is difficult to obtain a high uniformity, in terms of film thickness (and in this case of the interference colour), on the whole surface to be coated, above all when it laterally extends and it is not a rotation solid.

In order to obtain this result, positioning inside the chamber has been studied; moreover, masks and frameworks have also been created with suitably studied shape, material and thickness to modify the distribution of electric field and plasma inside the reactor.

With respect to coatings with interference colours already existing on the market (ex. Ti/TiO2), the chromatic effect is obtained starting from cheaper materials (silicon and iron are much widespread in the world and cheaper than Ti). Moreover, as results from bibliographic and patent searches performed by the inventors, the commercial use of interference coatings based on silicon oxide (or silicon oxide with mixtures of other oxides) with a similar architecture as the one already described here, is not present.

Finally, the deposited coaring, in addition to its decorative features, offers an increase of hardness and wear resistance: for this reason, continuing the comparison with titanium oxide, silicium oxide is harder.

Therefore, with the manufacturing method described here starting from very cheap starting materials (ex. Si and Fe), it is possible to generate an architecture of coatings that offers brilliant and pleasant colours, both with a light colouring effect and with a intense colouring effect.

Moreover, with respect to many other commercially available coatings, the coloured coating obtained here is not produced with anodisation treatments (such techniques have environmental impact problems, in particular as regards disposing liquid flows), but through deposition techniques from vapour phase, that are characterised by a null or very low environmental impact and by an efficient use of rough materials and energy. The product coatings further allow increasing the surface hardness of the parts made of die-cast alloys and, consequently, the wear resistance. As previously stated, the vapour phase deposition processes are deemed as having a very low environmental impact, since they do not require the use of solvents, imply the use of small amounts of material for making the coatings and the thereby obtained product is characterised by a high thermal mechanical and chemical stability. The coating can be removed through simple sanding, at the end of life of the part, thereby making, after this treatment, the coated part made of a die-cast aluminium alloy capable of being recycled according to usual procedures developed for such alloys. On the other hand, the coating, should it be removed from the component, would not have environmental impact problems, apart from the possible intrinsic obnoxiousness or allergenic feature of the metallic element selected for the reflecting layer (ex. Ni). However, it is necessary to note that, even in this case, the addition of allergenic metals can be limited to the single reflecting layer, inside the coating architecture, or extended, but in minimum amounts, to the transparent layer. Both layers are anyway extremely thin, on the order of nanometers, and, therefore, the possible presence of such metals is very limited. In case of deposition of the first layer in a purely metallic form, such metals are embedded into the external oxide layer, which is inert (and therefore they cannot be released). Also during the removal of the coating and the recycling of the part, the metal would be a minimum fraction of the removed powdery residual.

Summarising, the inventive process allows obtaining the following innovative technical features:

1. Deposits at least with a double layer, with interference colouring effect (cheaper and harder than those based on the Ti+TiO2 system, which is known and object of previous patents) and a protecting effect, obtained through vapour phase deposition techniques that can be applied to substrates made of different materials, in order to make both their decorative effect and their hardness under wear conditions, nobler.

2. Such deposit is composed of a reflecting metallic layer (Fe, Ni, Cr, Ti, etc.) and of a transparent oxide layer with a controlled thickness, based on a silicon oxide or other element of the Group IVA of the Periodic Table or a mixture of such oxides with oxides of transition metals (ex. Iron) or with metals belonging to the Lantanide group. The reflecting metallic layer produces the reflection of incident light; the transparent oxide layer, when thickness changes, generates different colours.

3. The introduction of metal oxides in the most external layer of silicon oxide increases its refraction index, improving chromatic yield and interference effect.

4. The first metallic layer is obtained through deposition with Physical Vapour Deposition, PVD techniques (such as for example Sputtering, E-Beam, Cathode Arc, Thermal Evaporation, Ion Beam, etc.), the second layer can be obtained through PVD deposition techniques or through Plasma Enhanced Chemical Vapour Deposition (PECVD) techniques or another CVD technique.

5. The deposition of a layer based on silicon oxide through PECVD can also allow obtaining, in the same process stage, a surface functionalisation, for example making hydrophilic, hydrophobic or anti-finger the surface of the thereby-generated interference coating. Should the same effect be obtained on the Ti/TiO2 system, it would be necessary to provide a further treatment and a further layer, increasing the manufacturing costs.

The main technical problems that have been solved when developing such coatings are those related to the definition of various colours and to obtaining a deposition uniformity also on complex shapes (ex. curvilinear and with numerous edges). In this case, the coating uniformity in terms of thickness is fundamental, since it also guarantees the colour uniformity.

Therefore, with the manufacturing process here described, starting from a single die-casting die, it is possible to quickly generate numerous furniture modules or elements 1 under conditions of jets of an aluminium alloy, in particular die-cast ones, to pre-treat the surface according to different processes and then finish them, with a treatment variation, with a deposit of brilliant and pleasant colours.

Moreover, the following assembling of the various decorated modules can be easily performed by an end user in order to build the global furniture element 1. In fact, the modules 1 joined with a simple engagement and without needing to fasten them with small blocks, generate an already finished and ready-to-use furniture element, that can be abutted onto an internal or external wall or can create a dividing wall, and since it is self-bearing, it requires only a few anchoring points and does not absolutely need to use supporting structures. The same user, in a simple way and with a frequency at will, can modify the design of the furniture element by simply mutually exchanging some modules or alternating modules obtained with various surface treatments and/or, as treatment variation, interference treatments with different thickness and therefore capable of generating a global polychromatic furniture element (joining different modules) according to different possible geometries.

These aspects are a distinctive feature of the invention. In fact, though there are numerous other solutions for decorating the walls (application of tiles, stuccos, paintings, etc.) or for generating dividing walls (constructions made of bricks, gypsum-card, beton gas, glass tiles, etc.), they require however several working stages for preparing walls, fastening or supporting the elements and finishing the surfaces.

Moreover, all these solutions, once defined and built, can be modified only through a partical or complete destruction and reconstruction.

A further advantage of the present invention, when using the variation with die-casting, consists in that, though there are other furniture or coating elements for facades made of an aluminium alloy, they are almost always manufactured starting from plates or slabs obtained through plastic deformation and not die-casting, and anyway none of them operates by restraining. This however limits their shape complexity and their production flexibility. Moreover, colouring of such elements is almost always obtained with anodisation treatments, while obtaining the colourings through the treatment variation, deposition techniques from vapour phase, described in the treatment variation part, allows obtaining greater hardness, wear and corrosion resistance, in addition to unique chromatic characteristics, due to the presence of interference colouring.

Titanium-coated aluminium slabs are also marketed, afterwards subjected to surface oxidation processes through electrolytic baths, but such techniques have environmental impact problems, in particular as regards liquid reflow disposal. In this case, instead, the process has a practically null environmental impact, since it does not require the use of solvents, implies the use of small amounts of material for performing the coatings, and the thereby-obtained product is characterised by a high thermal, mechanical and chemical stability.

The coating, should it be removed from the component, would not anyway have environmental impact problems, apart from the possible intrinsic obnoxiousness or allergenicity of the metallic element selected for the reflecting layer. However, the metallic layer is extremely thin, on the order of nanometers, and is protected when operating by the overlying oxidic layer.

Summarising, the inventive furniture modules or elements 1 allow creating self-supported decorative walls for interiors and exteriors, light filters and sun shades, coatings that require minimum fastening elements and do not require laying with further masonry works.

The realisation of furniture modules 1 with a simple and efficient restrain allows generating a self-bearing structure capable of operating as furniture element without needing further finishing operations.

The product creates a new behavioural assumption for the end user, since it does not need specialisations or specialists for its laying, does not need other binding materials or supporting structures.

Flexibility, variety of possible furniture and shape solutions provides the chance, for the user, to re-use the objects “modules” 1 with infinite solutions and places, making the product life cycle almost endless, apart from that, upon completing the cycle itself, one wants to benefit from the product recyclability.

A further advantage of the invention is the use of an already recycled material (secondary aluminium alloys), that, even in case of disposal, always has an economic value.

Obtaining furniture modules 1 occurs by manufacturing with the die-cast technique, that is efficient and cheap, but widely adopted for mechanical parts. With this use, such technique allows obtaining pieces with a complex shape in big production volumes, in short times and with reduced costs.

The inventive furniture modules find main, but not limiting, application area in architectures of interiors and exteriors, such as coatings of walls and ceilings, furniture elements or modules, self-bearing dividing walls, light filters, sun shades. 

1. Self-bearing furniture module or element (1), made of metal, in particular of an aluminium alloy, preferably a die-cast aluminium alloy, and comprising: an elongated supporting structure (3) comprising two ends (5, 7) and equipped with at least one first engaging element (9, 11) placed at one of the ends (5, 7); at least one bearing component (12, 14) connected to the supporting structure (3) adjacent to the first engaging element (9, 11); and at least one engaging component (16, 18) by restraining, connected to the supporting structure (3), said engaging component (16, 18) being equipped with at least one second engaging element (20, 22) and being adapted to engage a respective bearing component (12, 14) of another furniture module or element through an operating coupling of their corresponding first and second engaging elements (9, 11 and 20, 22); characterised in that the bearing components (12, 14) are two, each one shaped as a regular geometric figure with a maximum overall size of a same order of magnitude of the length of the supporting structure (3), and the engaging components (16, 18) are also two, each one shaped as the same regular geometric figure of the bearing components (12, 14) with a maximum overall size of a same order of magnitude of the length of the supporting structure (3), the overall size of the engaging components (16, 18) being greater than the overall size of the bearing components (12, 14), in order to be able to place an engaging component (16, 18) of a first furniture module or element (1) around and in engaging contact with the corresponding bearing component (12, 14) of a second furniture module or element _(1), when the first and the second modules (1) are mutually joined.
 2. Furniture module or element (1) according to claim 1, characterised in that the bearing components (12, 14) are two, shaped as a circle with a diameter of a same order of magnitude of the length of the supporting structure (3), and the engaging components (16, 18) are also two, shaped as a circle with a diameter of a same order of magnitude of the length of the supporting structure. (3), the diameter of the engaging components (16, 18) being greater than the diameter of the bearing components (12, 14), in order to be able to place an engaging component (16, 18) of a first furniture module or element (1) around and in engaging contact with the corresponding bearing component (12, 14) of a second furniture module or element (1), when the first and the second modules (1) are mutually joined.
 3. Furniture module or element (1) according to claim 1 or 2, characterised in that it is made in a single piece.
 4. Furniture module or element (1) according to claim 1, 2 or 3, characterised in that the bearing components (12, 14) are placed at the two ends (5, 7) of the supporting structure (3) along its longitudinal axis, while the bearing components (16, 18) are centrally placed with respect to the supporting structure (3) and along an axis which is perpendicular to the longitudinal axis of the structure (3) itself, thereby making a “four-leaved clover”-shaped arrangement of the furniture module or element (1).
 5. Furniture module or element (1) according to claim 1, 2 or 3., characterised in that the bearing components (12, 14) are two, of a circular shape, and are arranged with their diameter axes mutually perpendicular, and the engaging components (16, 18) are also two, of a circular shape, with a diameter greater than the diameter of the bearing components (12, 14), with their diameter axes mutually perpendicular and respectively coinciding with the diameter axes of the bearing components (12, 14), in order to be able to place an engaging component (16, 18) of a first furniture module or element (1) around the corresponding bearing component (12, 14) of a second furniture module or element (1), when the first and the second modules (1) are mutually joined.
 6. Furniture module or element (1) according to claim 1, characterised in that it further comprises a coating comprising at least one first reflecting layer and at least one second transparent layer, both layers being composed of a mixture of two components with correspondingly and proportionally varying relative molar fractions: 1) metallic material, for example iron, nickel or titanium, and 2) a material based on silicon oxide or silica, or an oxide of another element of Group IVA of the Periodic Element Table.
 7. Process for manufacturing a furniture module or element (1) according to claim 6, comprising the steps of: providing a die, particularly for die-casting; making the furniture modules or elements (1) under conditions with metal jets, particularly aluminium alloy; pre-treating the furniture module or element (1); washing the furniture module or element (1); depositing on the furniture module or element (1) at least one first reflecting layer and at least one second transparent layer, both layers being composed of a mixture of two components with correspondingly and proportionally varying relative molar fractions: 1) a metallic material, for example iron, nickel or titanium, and 2) a material based on silicon oxide or silica, or an oxide of another element of Group IVA of the Periodic Element Table.
 8. Process according to claim 7, characterised in that said step of washing comprises the sub-steps of: blowing with compressed air, to remove the presence of contaminants as dust deposited on the surface; keeping in a closed chamber, under vacuum conditions and at a temperature included between 100 and 200° C.; degreasing through solvents, such as acetone or ethyl alcohol, to remove oily or greasy contaminants that can still be deposited on the metal surface.
 9. Process according to claim 7, characterised in that the relative fractions of the two components change, in order to change the refraction index, with values that, in the first layer, range from 0 to 1 for the metallic material and from 1 to 0 for the oxide-based material, while in the second layer range from 0 to 0.9 for the metallic material and correspondingly from 1 to 0.1 for the oxide based material.
 10. Process according to claim 7, characterised in that the first reflecting layer is obtained through deposition with Physical Vapour Deposition, PVD, techniques.
 11. Process according to claim 10, characterised in that said PVD techniques are Sputtering, AND-Beam, Cathode Arc, Ion Beam.
 12. Process according to claim 7, characterised in that the second transparent layer is obtained through, PVD deposition techniques or with Plasma Enhanced Chemical Vapour Deposition (PECVD) techniques or other CVD technique.
 13. Process according to claim 7, characterised in that said step of pre-treating the furniture module or element (1) is performed through sanding, polishing, brushing, tumbling or buffing. 